Generally switching devices can be expanded with one or more auxiliary contact blocks, which can be built onto the switching device on a housing or housing part or are already integrated in the device. The auxiliary contacts here serve for a specific function, for example to communicate the status of the main contact poles. In the case of power circuit breakers they are used to display the on, off or trigger status of the device.
Actuating units are deployed to allow actuation of the auxiliary contacts. In the case of contactors these are actuated for example with electromagnetic drives; in the case of power circuit breakers this is done for example with mechanical control units (latching mechanisms). Actuation of the mechanical control apparatus or electromagnetic drive brings about the closing or opening of the contacts, which are connected by way of the actuating units to the mechanical control unit or the electromagnet. Since there is now an increasing trend toward compact motor starter apparatuses for example—corresponding to one of the above-mentioned switching device combinations—auxiliary contacts of suitable form are required, as with known auxiliary contact blocks, in which for example external auxiliary contacts are built onto the switching device on different planes, the wiring outlay and space requirements are significant.
Auxiliary contact blocks for expanding a switching device with auxiliary contacts disposed in a plane with contact bridges and associated fixed contact pieces as well as with at least one contact slider, which can be equipped with at least one auxiliary contact pair, it being possible to actuate the contact slider by way of an actuating unit, which can be connected to at least one switching apparatus for switching the at least one switching point are known from DE 196 36 109 C1, WO 2005/101444 A, DE 101 18919 A1 and from DE 875 681 B. Further contact apparatuses are also known from DE 22 19 428 C2, DE 102 96 272 T5 and from DE 10 2004 034 859 A1.